1. Field of the Invention
The present invention relates to a zoom lens, which is compact and lightweight, and is used in, e.g., a video camera.
2. Related Background Art
Conventionally, most of zoom lenses for video cameras are constituted by four lens units to have positive, negative, negative, and positive refractive powers, or positive, negative, positive, and positive refractive powers in order from the object side, and attain zooming by moving the second and third lens units or the second and fourth lens units.
In recent years, demand for a compact, lightweight, and high-performance zoom lens has become stronger. In general, as means for attaining further size and weight reductions of a zoom lens, a method of increasing the powers of the respective lens units is used. However, this method increases various aberrations, and deteriorates the performance of the lens.